var daohang = document.getElementsByClassName("daohang");
//给页面绑定滑轮滚动事件  
window.onmousewheel = function (e) {
    if(e.deltaY>0)
    {
        console.log("下");
        // daohang.style.position = "fixed";
    }
    else if(e.deltaY < 0)
    {
        console.log("上");
        // daohang.style.position = "static";
    }
}

var mouseenterFc = function(dom){
    var a = dom.getElementsByClassName("titlediv");
    a[0].style.backgroundColor = "yellowgreen";
    a[0].style.top= "-100px";
    a[0].style.height= "90px";
}
var mouseleaveFc = function(dom)
{
    var a = dom.getElementsByClassName("titlediv");
    a[0].style.backgroundColor = "";
    a[0].style.top= "";
    a[0].style.height= "";
}